This proposal describes NMR relaxation measurements on protons, deuterium, carbon, and other rare spin nuclei in protein crystals, protein powders and protein solutions which will directly define the state of water in protein systems as fundamental background for interpretation of more complex systems such as tissues. The nature of the changes in protein structure brought about by the addition of water to a dry protein system will be investigated by study of the protein NMR spectra and relaxation of rare spins or spin labels in the solid state. NMR dispersion measurements will be made to define the nature of the low frequency processes in semi-solid protein systems. The nature of the changes in the protein structure and dynamics on crystallization will be investigated by observation of rare spin resonances in these different physical states. Protein side-chain motions in the crystal and other protein environments will be studied and attempts will be made to define the spectral density functions that may characterize motions in various parts of the protein structure in the solid or rotationally immobilized aqueous state.